The branch of National Gallery at Nafplion is housed in a neoclassical building which has been restored, converted, and fully equipped for museum use with funds from the Onassis Foundation.

The mansion was built in 1905 based as the home and private clinic of George Minaios, doctor and later mayor of Nafplion. The mansion was used for many different purposes until it was abandoned. Later on, in a ruinous condition, it became the property of the Municipality of Nafplion.

The renovation and refurbishment works included: structural reinforcement, restoration of the architectural elements of the facades, incorporation of new electromechanical equipment required for a contemporary exhibition space, new interiors, decorations etc.